When water is electrolysed , volume of hydrogen and oxygen are evolved in the ratio of

Options

A. `1:1`
B. `1:8`
C. `1:18`
D. `2:1`

Explanation

To determine the volume ratio of hydrogen and oxygen evolved during the electrolysis of water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Electrolysis Reaction**:
The electrolysis of water can be represented by the following chemical equation:
\[ 2H_2O(l) \rightarrow 2H_2(g) + O_2(g) \]
This equation indicates that 2 moles of water produce 2 moles of hydrogen gas and 1 mole of oxygen gas.

2. **Identify Moles of Gases Produced**:
From the balanced equation, we see that for every 2 moles of water, 2 moles of hydrogen (H₂) and 1 mole of oxygen (O₂) are produced.

3. **Establish Volume Relationship**:
According to Avogadro's law, the volume of a gas at constant temperature and pressure is directly proportional to the number of moles of the gas. Therefore, the volume ratio of hydrogen to oxygen will be the same as the mole ratio.

4. **Calculate the Volume Ratio**:
From the reaction:
- Moles of H₂ = 2
- Moles of O₂ = 1

The volume ratio of hydrogen to oxygen can be expressed as:
\[ \text{Volume ratio} = \frac{\text{Volume of } H_2}{\text{Volume of } O_2} = \frac{2}{1} \]

5. **Final Answer**:
Therefore, the volume of hydrogen and oxygen evolved during the electrolysis of water is in the ratio of:
\[ \text{Volume ratio} = 2:1 \]